star formation in the milky way and its neighbors in the mid-ir
DESCRIPTION
Star Formation in the Milky Way and its Neighbors in the Mid-IR. Chris Wilson McMaster University. Outline. Catching massive star formation “in the act” Forming massive star clusters in nearby galaxies Theme: synergies between JWST and FIR/submm telescopes (Herschel, ALMA). - PowerPoint PPT PresentationTRANSCRIPT
Star Formation in the Milky Way Star Formation in the Milky Way and its Neighbors in the Mid-IRand its Neighbors in the Mid-IR
Chris Wilson
McMaster University
OutlineOutline
1) Catching massive star formation “in the act”
2) Forming massive star clusters in nearby galaxies
Theme: synergies between JWST and FIR/submm telescopes (Herschel, ALMA)
SED of a massive young stellar objectSED of a massive young stellar object
Figure from Beuther et al. 2010, A&A
JWST Herschel
ALMA
Integrated SEDs of Integrated SEDs of galaxiesgalaxies
Figure from Galliano 2004, PhD thesis
HerschelJWST
ALMA
The advantage of angular resolution:The advantage of angular resolution:M81 near the dust emission peakM81 near the dust emission peak
Spitzer MIPS 160 um Herschel PACS 160 um (Gordon et al. 2004) (Bendo et al. submitted)
Searching for buried protostars:Searching for buried protostars:Not all “Starless cores” are starlessNot all “Starless cores” are starless
• Spitzer 24 um observations of L1521f from c2d survey reveal a protostar in an evolved “starless” core
Bourke et al. 2006, ApJ
Catching the start of high-mass star formationCatching the start of high-mass star formation
• Infrared dark cloud with an IRAS protostar
• 24-500 um reveals new protostar plus apparently starless cores
Beuther et al., 2010, A&A
Many candidates from Herschel surveysMany candidates from Herschel surveys
• HOBYS project mapping massive GMCs within 2 kpc (Motte et al. 2010, A&A)
• Example: NGC 7538 imaging reveals cores and filaments (Reid et al., in prep.)
20’
Sites of Massive Star Formation in the LMCSites of Massive Star Formation in the LMC
Indebetouwet al. 2008,AJ
Spitzer:R/G/B=24, 8,4.5 um
SEDs and luminosity functionSEDs and luminosity function
• Lots of molecular gas but little evidence of star formation before Spitzer observations
• Sensitive to protostars > 3 Mo
Indebetouw et al. 2008
Lo
N
Massive Young Stellar Objects in the LMCMassive Young Stellar Objects in the LMC
• Spitzer SAGE discovered 1800 massive YSO candidates (Whitney et al. 2008, Gruendl & Chu 2009)
• First Herschel strip reveals 207 embedded candidate YSOs (40% previously unknown)
Sewio et al. 2010 A&A
The youngest massive protostars in the LMCThe youngest massive protostars in the LMC
• SAGE survey missed youngest embedded sources since only went to 24 um
• Spectroscopic confirmation of YSOs through ice absorption (or maybe Silicate or PAH emission) – 300 YSOs
confirmed with Spitzer (i.e. van Loon et al. 2010, AJ)Sewio et al. 2010
Mid-IR Imaging and Spectroscopy with JWSTMid-IR Imaging and Spectroscopy with JWST
• Spectroscopic confirmation of lower luminosity YSOs• 24 microns: 1” = 0.25 pc
– Can isolate individual stars/binaries– May be able to identify dense compact young clusters
• Imaging should detect protostars below 1 Mo• What are the effects of metallicity on the formation of
individual stars?
Physical conditions in the ionized gasPhysical conditions in the ionized gas
R/G/B =8 um, B band,X-ray
Indebetouw et al. 2009, ApJ
Spectrum of entire 30 Doradus nebulaSpectrum of entire 30 Doradus nebula
Indebetouw et al. 2009, ApJ ~4’x4’ region
Note risingMIR continuum
Mid-IR spectroscopy inside an HII regionMid-IR spectroscopy inside an HII region< Brightest source< low excitation region< CO emission peak
< Prominent MIR source outside main bubble
< R136 cluster< Diffuse region, harder
radiation field< Known WN6 star R145
Indebetouw et al. 2009
Star cluster formation in M51Star cluster formation in M51
Mentuch et al., in prep., Herschel VNGS image
Calzetti et al. 2007, Spitzer SINGS image
Individual regions in M51Individual regions in M51
24 um 70 um
Spitzer SINGS image,Calzetti et al. 2007
Herschel VNGS image,Mentuch et al., in prep.
Individual regions in M51Individual regions in M51
24 um 70 um
Spitzer SINGS image,Calzetti et al. 2007
Herschel VNGS image,Mentuch et al., in prep.
Antennae: the closest Antennae: the closest major mergermajor merger
• Wilson et al. 2000, ApJ
• Whitmore et al. 1999, AJ
CO overlaid onHST optical image
The Antennae in cool dust emissionThe Antennae in cool dust emission
• Two infrared bright regions in overlap region with different 6cm/FIR indicating different ISM properties
• Herschel PACS data: Klaas et al. 2010, A&A
The Antennae in cool dust emissionThe Antennae in cool dust emission
• Two infrared bright regions in overlap region with different 6cm/FIR indicating different ISM properties
• Herschel PACS data: Klaas et al. 2010, A&A
Complex mid-IR spectra Complex mid-IR spectra in the Antennaein the Antennae
• Wilson et al. 2000, ApJ
NeIII
NeIIPAH
risingcontinuum
ISO 15 umimage
ISO CVF spectra
Complex mid-IR spectra Complex mid-IR spectra in the Antennaein the Antennae
• Wilson et al. 2000, ApJ
NeIIINeII
PAH
Complex mid-IR spectra Complex mid-IR spectra in the Antennaein the Antennae
• Wilson et al. 2000, ApJ
PAH NeII
Mid-IR Spectroscopy with JWSTMid-IR Spectroscopy with JWST
• Is the hot continuum source in the Antennae co-located with the strong NeIII emission?
• 12 microns: 0.5” = 50 pc– Can resolve an individual molecular cloud (100
pc), but not a cluster-forming core (1 pc)
• Extended sources may need small spectroscopic mosaics
• Can we locate other targets with rising continuum in Antennae? M51? Etc?
Comparing the Antennae peak with Comparing the Antennae peak with the R136 star cluster in the LMCthe R136 star cluster in the LMC
Indebetouw et al 2009, ApJ Brandl et al. 2009, ApJ
10 um 30 um10 um 30 um
SummarySummary• MIRI on JWST has great promise for studying
individual star and star cluster formation, both in our own Galaxy and in other galaxies
• Great synergies between JWST and ALMA for high resolution imaging and spectroscopy!
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